Conversion of hydrocarbons



Patented June 25, 4194c CONVERSION OF HYDROCARBONS Funk L'Moore, Beacon,N. Y., asslgnor to The Ten: Company, New York, N. Y., a corpora.-

tlon of Delaware Application February 12, 1942, Serial No. 430,575

8 Claims. 1

This invention relates to the conversion of hydrocarbons and has to dowith the preparation of a fluid catalyst suitable for effectingisomerizw tion of hydrocarbons, and the employment of such a catelystfor this purpose.

The invention contemplates effecting isomerizatlon of hydrocarbons bythe action of an actlve isomerizotlon catalyst formed by reacting ametallic halide and a hydrocarbon in the presence of on oxygencontainlng gas under condiditlons so do to form an oxygenatedhydrocarhon-metallic halide complex mixture.

More specifically the invention contemplates subjecting a. feedhydrocarbon to contact with a. fluid catalyst prepared by reactingaluminum halide and a saturated hydrocarbon in the presonce or a. smallamount of carbon monoxide under conditions so as to form a mixture ofcxygenated hydrocarbon and non-oxygenated by drocarbon-metullic halidecomplexes containing in addition some free aluminum halide. The feedhydrocarbon and fluid catalyst mixture are main tallied underisomcrizing conditions adv/ante,-

geously in the presence of an activator capable of affording hydrogenhalide so as to cause substantial conversion into isomerizedhydrocarboos. Advantageously the reaction i carried out in the presenceof a substantial amount of ettraneous hydrogen or hydrogen containinguse so as to realize a'relatively high conversion to isomerlzedhydrocarbons without the occurrence of substantial cracking or otherside reactions, or

while confining the occurrence of cracking and other side reactions torelatively small extent.

It is already known to effect conversion reactlons including catalyticlsomerlzation of hydrocarbon; in the presence of a large amount ofhydrogen. For example, dOuville, Evering and Oblad Patent 2,260,279discloses eflecting catalytlc lsomerlzation of hydrocarbons under ahydrogen pressure ranging from about 800 to 4000 pounds per square inch.

However, in accordance with the present inzso-csso) I action since undersuitable conditions of coerc tion straight-chain gasoline hydrocarbonssuch of this invention than when used in conjunction with a. catalystconsisting only of ohuuiuum chloride, aluminum chloride-hydrocarboncomplex or aluminum chloride mixed with such complex. The reason forthis is not understood but nevcrthelesgthe phenomenon appears to existas Wi danced by the following date, obtained in batch operations inwhich normal pentane was treated in the liquid phase with u fluidmixture comprising anhydrous aluminum chloride and elumlnumchloride-hydrocarbon complex ot a, tem

perature of about 160 F. and for 9. period of about u hours.

In such instance a quantity of normal pentone was charged to a reactionvessel to which was also charged anhydrous aluminum chlorldeond aluminumchloride-hydrocarbon complex as well as some hydrogen chloride.- Theamount of anhydrous aluminum chloride charged was equivventlon theisomerlzatlon reaction may be carried out under relatively lowerhydrogen pressure to obtain superior results from the standpoint ofrealizing high conversion: to laomerized hydrocarbon; while substantiallavoiding cracktlons.

in: or at least materially reducing the amount of cracking occurringduring the reaction.

Th employment of a fluid catalyst mixture clent to 10% by weight of thenormal pentane charged. while the hydrogen chloride amounted to 1% byweight of the normal pentane charged.

The aluminum chloride-hydrocarbon complex charged to the vessel amountedto about 13% by weight of the normal pentane charged and this complexcomprised material accumulated from previous operations in whichgasoline hydroccrbons were treated with aluminum chloride and hydrogenchloride under lsomerizlng condi- It had a density or about 1.3 gramsper cubic centimeter.

The data tabulated below were obtained in comparative runs: (1)employing the aluminum chloride plus aluminum chloride-hydrocarboncomplex in the absence or carbon monoxide and composed at least insubstantial part of an oily.-v

genoted hydrocarbon-metallic halide complex as is contemplated by thepresent invention provideo a uperior catalyst for an somerlzatlonrehydrogen; .(2) employing the aluminum chloride complex mixture in thepresence 01' carbon monoxide but in the absence of hydrogen; (3) cm- 9F111: the aluminum chloride complex' mixture in the presence or hydrogenbut in the lblmee n-pentane .i Weight per cent normal pentane of carbonmonoxide; and (4) employing the aluminum chloride complex mixture'in thepresenceof both hydrogen and carbon monoxide.

Run

Per cent carbon monoxide in'the reaction mixture by weight of n-pentanePressure of hydrogen over the reaction mixture, pounds, per square inchgauge Composition 0 hydrocarbon product, per cent by weight:

0| and lighter hydroearbons Isopentane Normal pentaneul Hydrocarbonsheavier then converted to i Isop'entano obtainedas per cent of normalpentane converted As shownin this table when eflecting isomerization inrun A in the absence of either oxygenated compounds or hydrogensubstantial cracking occurred as evidenced by the obtaining of 69.4% ofC4 and lighter hydrocarbons. While 95.1% of the normal pentane chargedwas actually converted, nevertheless only 21.0% of the convertedmaterial wasisopentane.

Referring to run 13 in which carbon monoxide was charged so thatoxygenated hydrocarbonaluminum chloride complex existed in the reaction,it will be seen that the amount of cracking was reduced and theconversion to isopentane was somewhat higher, namely, 25.2% of thenormal pentane converted.

In run C which was made in the absence of the oxygenated compounds, butmaintaining a hydrogen pressure of 210 pounds, 64.9% of materialcorresponding to C4 and lighter hydrocarbons was obtained and the yieldof isopentane was still low, namely, 24.6% by weight of the normalpentane converted.

In run D where both hydrogen and carbon monoxide were used in thereaction the amount of cracking was very materially reduced since thematerial corresponding to C4 and lighter hydrocarbons amounted to only0.4% while the isopentane obtained amounted to 77.0% of the normalpentane converted.

In run E the amount of carbon monoxide employed was increased and at thesame time the hydrogen pressure was reduced to 40 pounds.

Under these conditions the treated hydrocarbonscontained 69.1%isopentane or in other words the isopentane obtained amount to 82.5% ofthe total normal pentane converted.

In the foregoing experiments, for example, runs B, D and E, theoxygenated'hydrocarbon complex was formed as an incident to or a part.of the isomerization reaction in the reaction vessel.

However, a preferred form of the invention in-. volves preparing apreformed catalyst mixture containing the oxygenated compounds and thenemploying the preformed catalyst mixture in a separate reaction zonewherein the isomerization reaction is carried out. In-such case thecatalyst mixture could be prepared by reacting anhydrous aluminumchlorideand a portion of the feed hydrocarbon in the presence of carbonmonoxide and some hydrogenchlorido in a separate vessel.

portion of about 0.1 to 1.0 parts of anhydrous aluminum chloride to onepart by weight of normal pentane. Carbon monoxide is injected into thismixture in an amount ranging from about 1 to 16% and preferably about 4to 5% by weight of the aluminum chloride added. Hy-

drogen chloride is added to the mixture to-the extent of about 1% byweight of the hydrocarbon. This mixture is then subjected to thoroughstirring for a period of from about 1 to 4 hours while maintained at atemperature in--the range about 70 to 200 F. thereby obtaining a fluidcatalyst mixture comprising free aluminum chloride, aluminumchloride-ketone H: and

The preformed catalyst can then be transferred to a suitable reactionvessel wherein it is brought into contact with a stream of feedhydrocarbon and maintained under isomerizing conditions.

Instead of using pentane the catalyst can be prepared by reacting otherparafllns, either iso or normal, with the aluminum chloride to preparethe preformed complex.

One method of employing the preformed catalyst is illustrated in theflow diagram shown in the accompanying diagram to which reference willnow be made.

Referring to the. drawing a feed hydrocarbon such as normal pentane isdrawn from'a source not shown and conducted through a pipe I to a heater2 wherein it is heated to the desired reaction temperature which mayrange from about 100 to 300 F.

The heated feed is then passed through a pipe 3 to the lower portion ofa reaction vessel 4.

In this instance the reaction vessel 4 advantageously comprises a towermaintained substantially filled with the preformed fluid catalystmixture. The heated hydrocarbon feed being of lower density than thecatalyst mixture rises upwardly through the catalyst and undergoesconversion during its upward flow through the reaction tower. Packingmaterial may be provided in the tower for facilitating contact'betweenfeed hydrocarbon and catalyst.

Hydrogen chloride or other suitable activator capable of providinghydrogen halide is introduced from a source not shown through a pipe I.

Fo example, normal pentane may be mixed with anhydrous aluminum chloridein thc'pr0-' or may be introduced into the charge stock prior .-topassage through the-heate stream of'feed hydrocarbon.

The reacted hydrocarbons accumulate in the upper portion of the towerand are continuously I withdrawn thereirom through a pipe 1 anddischarged into the lower "portion of a fractionator or stripping towerl. The tower 8 is advantageously operated so as to strip gaseousmaterials such as hydrogen and hydrogen chloride from the reactedhydrocarbons. The gas is discharged from the tower through a pipe I andmay be all or in Part returned through a pipe II for recycling to thereaction.

Other means may be provided for separating the hydrogen and hydrogenchloride from the reacted hydrocarbons and returning the separated gasesindividually or collectively, all, or in part, to the reaction.

The stripped hydrocarbon reaction products I are th'en conducted to asecond tower ii for the purpose of efiecting further fractionation. Thistower may be operated so as to take overhead a fraction comprisingisoparafllns and unreacted feed hydrocarbon, the residual fractionwithdrawn from the bottom of the tower comprising heavier hydrocarbons.On the other hand the fractionation may be eflected so as to segregatefractions of any desired boiling range. For example, a relatively lowboiling fraction may be removed through a pipe ll while an intermediatefraction may be removed through a pipe I. Obviously the fractionatingoperation may be adjusted in any manner desired to suit the particularneeds of the operator.

Provision is advantageously made for continuous or intermittentwithdrawal of used catalyst mixture from the bottom of the reactor 4through a pipe 20. As indicated it is desirable to provide adequatesettling space in both the bottom and top portions of the reaction towerso as to facilitate substantially complete separation betweenhydrocarbon andcataLvst phases. It is, of course. contemplated thatauxiliary settling chambers may be provided for this purpose if desired.

The catalyst phase, drawn off through the pipe I. may be conducted to asettler or accumulating drum I]. The heavier material settling out inthe settler Il may be drawn off through a pipe 22 and be discharged fromthe system or otherwise disposed of. This material may include heavyhydrocarbons or tarry material which it is desirable to discharge fromthe system.

The bulk of the catalyst phase accumulating in the settler II is drawnof! through a pipe 23 by a pump 24 and returned to pipes 2! and 20 .tothe upper portion ofthe reaction tower I.

Make-up catalyst is supplied from a mixer 2|. Thus, aluminum chloride,carbon monoxide, hydrogen chloride and hydrocarbon may be added to themixer it and the resulting mixture subjected to stirring and heating aspreviously described with reference to the preparation of the preformedcatalyst mixture.

:may be maintained within the reaction zone.

On the other hand it is contemplated that other types of reactionvessels may be employed, for example, an agitating vessel may be usedwherein the feed hydrocarbon and catalyst mixture are subjected toagitation by mechanical stirring apparatus or by continuous forcedcirculation of the reaction mixture through or within the reactionvessel.

It is usually desirable to remove impurities from the hydrocarbon feedto the reaction. Such impurities may comprise aromatic hydrocarbons,oleflnic hydrocarbon and sulfur compounds, etc. Removal of suchimpurities may be effected at least in substantial part by scrubbing theentering feed with a suitable scrubbing agent or by treating it with achemical reagent, for example, treatment with aluminum chloride. .Oneadvantageous method of effecting removal is to subject the feedhydrocarbon to scrubbing with spent complex drawn oil! from the reactionzone. This complex is thus used to dissolve and remove impurities fromthe feed hydrocarbon.

While the treatment of normal pentane has been described in connectionwith the description of the flow diagram, nevertheless it iscontemplated that the invention is applicable to the treatment of othergasoline hydrocarbons including normally gaseous hydrocarbons such asnormal butane. V

The temperature maintained during the isomerization reaction will dependupon the char acter of the feed hydrocarbon as well as upon otheroperating conditions, as for example, the proportion of hydrogen orother cracking inhibiting material employed in carrying out thereaction. When the charge consists essentially of normal hexane thetemperature may range from about 125 to 300 1'. If a hexane fraction ischarged which contain substantial amounts of naphthene hydrocarbonssomewhat higher temperatures are desirable, as for example, 200 to 350F. since naphthenes tend to inhibit the conversion reaction and thusnecessitate resorting to somewhat'higher temperatures. However, thepresence of such naphthenes is desirable from the standpoint ofpreventing to a still greater degree cracking and'other undesiredreactions.

If the charge consists essentially of normal butane the temperature mayrange from about 200 to 250' F.

The amount of hydrogen maintained in the reaction zone is advantageouslysumcient to ,maintain a hydrogen pressure over the reaction Theresulting catalyst mixture is drawn oi'f I,

from the mixer b a pump 2! and conducted through a pipe It communicatingwith the pipe 20 leading to the top of the reaction tower 4.

While the continuous withdrawal of catalyst phase from the bottom of thereaction tower 4 has been described nevertheless it is contemmixtureranging from about 40 or 50 pounds to 200 or 300 pound per square inchgauge. Where the preformed catalyst is prepared by reacting with carbonmonoxide in the proportionof about 1% by weight of the aluminumchloride, the hydrogen pressure maintained in the subsequentisomerization reaction is advantageously o! the order of about 200 or inthe range at to 800 7 pounds. With a catalyst which has been preparedusing larger amounts of carbon monoxide a corresponding reduction in thehydrogen pressure is permissible. Thus, where the preformed catalyst isprepared by reacting with carbon monoxide in the amount of about 15% byweight of aluminum chloride, the hydrogen pressure can be reduced toabout to 40 pounds per square inch gauge.

While aluminum chloride has been specifically mentioned as a componentof the isomerizatlon catalyst in the above-mentioned examples, it isintended that other-metallic halide catalysts may be employed such asaluminum bromide, zirconium chloride. boron triiiuoride, antimonychloride, metallic mixed halides, such as AlClal? and AlFaCl, etc., andmixed halides o! beryllium, zinc,

iron and aluminum and other metals and metalloids of groups 3 and 4 ofthe periodic system.

Suitable promoters may comprise besides hydrogen chloride, otherhydrogen halides, carbon tetrachloride, allryl chlorides, boron halides,carbon halides and halides of the other elements of the 4th group of theperiodic table.

Carbon monoxide has been described above in connection with thepreparation of the catalyst. However, it is contemplated that othersuitable oxygen-bearing substances may be employed such as nitrogenoxides and the like which are capable of providing oxygen for theformation of seatslyst comprising metallic halide-oxygenated hydrocarboncomplex.

Obviously many modifications and variations of the invention as aboveset forth may be made without departing from the spirit and scopethereof, and therefore only such limitations should be imposed as areindicated by the appended claims.

I claim:

1. A process for isomerizing saturated feed hydrocarbons which comprisesmaintaining within a reaction zone under isomerizing conditions a bodyof liquid isomerization catalyst consisting essentially of a liquidmixture of oxygenated hydrocarbon and non-oxygenated hydrocarbonmetallichalide complexes containing some iree 8 preformed by reacting aluminumchloride and a saturated parailin hydrocarbon in the presence of a smallamount of carbon monoxide and also in the presence of a small amount ofhydrogen chloride, subjecting said saturated feed hydrocarbons tocontact with said preformed catalyst body in the presence of hydrogenchloride, and eilectins substantial isomerization of said hydrocarbonsduring said contact.

4. The process according to claim 3 in which contact between saturatedfeed hydrocarbons and the catalyst body is eflected under a hydrogenpressure ranging from substantially above atmos pheric to about 300pounds.

metallic halide in lesser proportion by weight V than the complexes insaid body, said complex mixture being preformed by reacting a metallichalide selected from the halides o! metals oi groups 2, 3, 4, 5 and 8 ofthe periodic system and a saturated paraflln hydrocarbon in the presenceof a small amount of carbon monoxide and also in the presence of a smallamount of hydrogen halide, subjecting said saturated teed hydrocarbonsto contact with said preformed catalyst body in the presence of hydrogenhalide, and eflecting substantial isomerization of said hydrocarbonsduring said contact. 2. The process according to claim 1 in which thecontact between the saturated ieed hydrocarbons and the catalyst body iseffected under a hydrogen pressure ranging from above atmospheric toabout 300 pounds. a

3. A process for isomerizing saturated teed hy-.

drocarbons which comprises maintaining within a reaction zone underisomerizing conditions'a body oi liquid isomerization catalystconsisting essentially of a liquid mixture oi. oxygenated hydrocarbonand non-oxygenated hydrocarbon-slim inum chloride complexes containingsome free aluminum chloride in lesser proportion by weight than thecomplexes in said mixture, saidcomplex mixture having a specific gravityof about 1.3 to 1.4 grams per cubic centimeter and being from thehalides of metals of groups 2, 3, 4. 5 and f 8 of the periodic systemand a saturated parailln hydrocarbon in the presence oi a small amountof carbon monoxide and also in. the presence oi a small amount ofhydrogen halide, introducing'a stream of heated feed hydrocarbons to thebottom portion of said column of preformed liquid catalyst, causing theso introduced hydrocarbons to rise through the column by diiierence indensity in the presence or hydrogcnhalide. electing substantialisomerization of iced hydrocarbons during passage through the liquidcatalyst column, and continuously removing from the reactionzone astream of isomerized hydrocarbons which have passed through the catalystcolumn.

6. The process accordingto claim 5 in which the isomerization reactionis eflected under a hydrogen pressure mull g from substantially aboveatmospheric to about 300 pounds.

7. A continuous process for isomerixing saturated feed hydrocarbonswhich comprises maintaining within a reaction zone under isomerizingconditions a column 0! liquid catalyst consisting essentially of apreformed liquid mixture of oxygenated hydrocarbon and non-oxygenatedhydrocarbon-aluminum chloride complexes containing some free aluminumchloride in lesser proportion than the complexes in said mixture, saidcomplex mixture having a specific gravity o t-about 1.8 to

1.4 grams per cubiccentimeter and formed by reacting aluminum chlorideand a saturated paraiiin hydrocarbon in the presence of a small amountof carbon monoxide and also in the presence of a small amount oi.hydrogen chloride, introducing a stream or heatedieed hydrocarbons tothe bottom portion oi said column of pre-'- formed liquid catalyst,causing the so introduced hydrocarbons to rise through the column byditi'erence in density in the presence of h men halide, eiiectingsubstantial isomerisstion of iced hydrocarbons during passage thro h theliquid. catalyst column, and continuously removing from the reactionzone a stream or isomerised hydrocarbons which have passed through thecatalyst FRANK J. moons.

